Evaluation of the effects of multiple capture methods and immobilization drugs on mountain lion welfare

Using a dataset of 591 capture events between 2001–2019 in California, USA, we examined the impact of capture methods and immobilization drugs on mountain lion (Puma concolor) welfare. The 3 methods used to capture mountain lions were cage traps, trained hounds, and cable restraints. The drugs used to immobilize mountain lions were either tiletamine/zolazepam (Telazol®), ketamine/medetomidine, or ketamine/xylazine. Mortality occurred in 1.4% of captures, with only one mortality out of 310 captures occurring since 2012. We used a logistic regression framework to compare morbidity and vital parameters of mountain lions among the different capture methods and immobilization drugs used. Vomiting (a risk factor for developing aspiration pneumonia) was the most common severe risk factor associated with cage trapping and was only seen with the use of ketamine/medetomidine or ketamine/xylazine. Morbidity scores were not well predicted by any of the variables we accounted for. Animals immobilized with Telazol® were more likely to experience abnormal heart and respiratory rates, as well as high body temperatures, than those immobilized with the other two combinations. Although there are risks associated with each of the capture methods and drug combinations commonly used in mountain lion captures in California, our analyses demonstrated they are all relatively safe when following appropriate animal welfare practices. Our analyses suggested that unaccounted for factors are equally or more important in explaining injury and physiological abnormality rates, and we urge that agencies train personnel in best practices and conservative decision-making in order to assure that the welfare of the animal takes precedence over collaring. We suggest training on how to choose between several capture techniques, immobilization drugs and monitoring methods and how to reduce both detrimental effects to mountain lions and danger to humans.